The First Amendment to the U.S. Constitution is arguably one of the essential laws in America. It prohibits the enactment of any laws respecting the establishment of religion, impeding the free exercise of religion, abridging the freedom of speech, infringing on the freedom of the press, interfering with the right to assemble peaceably, or prohibiting citizens from petitioning for a governmental redress of grievances. It was adopted into the U.S. Constitution as a part of the first ten amendments (the first ten amendments to the United States Constitution, along with the Bill of Rights, comprising the American Bill of Rights) known as the "Bill of Rights" in 1791.
Freedom of Speech and the Press
Americans have traditionally been well informed, and the tradition of free speech is entrenched in people's minds. The First Amendment protects freedom of speech and the press and is most often cited in the United States when speaking about the matter. In essence, the right to speak and write freely on virtually any topic is a right that has been fiercely protected over centuries of American and English law.
As a rule, a person can say or write virtually anything about any person or topic, so long as it is not defamatory, and it cannot be held liable, either criminally or civilly, for such statements.
Certain types of speech are more readily protected than others. For example, commercial speech is heavily regulated because of the public interest in preventing false or misleading advertising.
Commercial speech is restricted to protect consumers by preventing misleading information from being advertised to them.
You cannot make false statements about another person or company without the risk of being sued for defamation. However, all opinions about people or companies should be because you cannot spread statements about another person or company without running the risk of being sued for defamation.
Freedom of thought and religion
When public opinion shifts, we often see bizarre political twists and turns. One of the most recent examples was a backlash against Islam in a post-9/11 America, where many sought to bar the practice of the faith or the construction of mosques in certain areas. Fortunately, these efforts were thwarted by the First Amendment, and Muslims remain free to exercise their faith in the United States.
Right to Assemble / Protest
In the United States, the right to assemble is historically derived from the First Amendment to the United States Constitution and statutory law. The right to assemble allows persons peacefully in a group setting, whether privately or publicly, as long as the purpose of the assembly is not to harm others.
Similarly, the First Amendment prevents the government from setting its agenda and ignoring the people's will. During the Civil War, Congress attempted to pass a rule prohibiting the discussion of emancipation. Congress later overturned this rule.